I have a new Honda Inverter eu3000is generator and noticed that when we use it, the UPS we have connected to it doesn't like the honda's output voltage and won't switch off battery.I measured the Honda output, and its 127volts which seems a bit high for a "load voltage". It appears the voltage doesn't change much between no load and load.I would have figured the honda inverter generator would have a nice clean regulated 120v output.Does anyone know if this generator should be outputting this voltage?

mstoetz1 wrote:Does anyone know if this generator should be outputting this voltage?I just looked at some videos I shot a few years ago and see that unloaded voltage of both Honda EU2000i gensets I owned was typically ~ 125 vac with the trailer plugged into the genset but everything inside including the converter turned off. Voltage did obviously drop as the load on the genset increased but would only drop to ~ 120 vac if I was running A/C which was certainly placing a maximum load on the genset.

127v is normal for an unloaded 3000. Gets to 123v with a good load.What are the specs for the UPS? Some things have a range of voltages they will work between but not over or under that.

How are you sure it's the voltage?

127V sounds perfectly reasonable to me. Normal tolerance for utility power is +/- 5% of nominal, or 114V to 126V. It sounds as though you're within that range to the precision of your measuring equipment. It may well be that the UPS has some other "reason" to not like the generator output--maybe it's looking for a ground to neutral bond and not finding one?

2oldman wrote:How are you sure it's the voltage?I'm only guessing actually. I guess I could put the generator on an oscilloscope to see what the output looks like.

Honda eu3000is - Output Voltage 127V | Good Sam Community

SoundGuy
Explorer
Dec 24, 2016
mstoetz1 wrote:
Does anyone know if this generator should be outputting this voltage?

I just looked at some videos I shot a few years ago and see that unloaded voltage of both Honda EU2000i gensets I owned was typically ~ 125 vac with the trailer plugged into the genset but everything inside including the converter turned off. Voltage did obviously drop as the load on the genset increased but would only drop to ~ 120 vac if I was running A/C which was certainly placing a maximum load on the genset.
BFL13
Explorer II
Dec 24, 2016
127v is normal for an unloaded 3000. Gets to 123v with a good load.

What are the specs for the UPS? Some things have a range of voltages they will work between but not over or under that.
2oldman
Explorer II
Dec 24, 2016
How are you sure it's the voltage?
DrewE
Explorer II
Dec 24, 2016
127V sounds perfectly reasonable to me. Normal tolerance for utility power is +/- 5% of nominal, or 114V to 126V. It sounds as though you're within that range to the precision of your measuring equipment. It may well be that the UPS has some other "reason" to not like the generator output--maybe it's looking for a ground to neutral bond and not finding one?
mstoetz1
Explorer
Dec 24, 2016
2oldman wrote:
How are you sure it's the voltage?

I'm only guessing actually. I guess I could put the generator on an oscilloscope to see what the output looks like.
2oldman
Explorer II
Dec 24, 2016
Ok, because (and I assume) a UPS could reject it for waveform or Hz issues. I know my Prosine 2.0 would...not that it rejected my Honda 2k. Oh, and don't forget ground issues.

I vaguely remember someone having to bypass his UPS due to these nuisance problems.
road-runner
Explorer III
Dec 24, 2016
The post above brings up a good point, the UPS could be rejecting the generator because of the floating output. If that's the case, a bonding plug could solve the issue. If the UPS is rejecting because of the voltage, the UPS is flawed. A frequency error is extremely unlikely. The eu3000i output waveform has small stairsteps at the inverter's switching frequency, which the UPS should easily accept.
MrWizard
Moderator
Dec 24, 2016
is this in the RV or the stick and brick

seems like the normal fridge, converter, water heater
would be enough load, to eliminate any usual problems

there was somebody on here once who had problems with his furnace control board, when using a generator at home
wa8yxm
Explorer III
Dec 24, 2016
127 volts, though on the high side of 120, is well within specifications for shore power. Very well within.
BFL13
Explorer II
Dec 25, 2016
What is the scenario here anyway?

I have seen on here where you might lose some TV time/settings if there is a delay in 120v transfer, so a UPS might help with that.

Is the UPS when on gen just to get you by till the inverter takes over? How can the transfer time be any better with a UPS than just staying on inverter and use any 120v available to run a battery charger to back up the supply to the inverter?